TITLE:	Tree codes for vortex dynamics:
	Application of a programming framework

AUTHORS:
	Sandeep Bhatt, Bellcore and Computer Science Department
	Pangfeng Liu,  Computer Science Department
	Victor Fernandez, Mechanical and Aerospace Engineering
	Norman Zabusky, Mechanical and Aerospace Engineering

DATE:	March 17, 1995

ABSTRACT:

This paper describes the implementation of a fast N-body algorithm for
the study of multi-filament vortex simulations.  The simulations
involve distributions that are irregular and time-varying.  We adapt
our programming framework which was earlier used to develop
high-performance implementations of the Barnes-Hut and
Greengard-Rokhlin algorithms for gravitational fields.  We describe
how the additional subtleties involved in vortex filament simulations
are accommodated efficiently within the framework.

We describe the ongoing experimental studies and report preliminary
results with simulations of one million particles on the 128-node
Connection Machine CM-5.  The implementation sustains a rate of almost
30% of the peak machine rate.  These simulations are more than an order
of magnitude larger in size than previously studied using direct
methods.  We expect that the use of the fast algorithm will allow us to
study the generation of small scales in the vortex collapse and
reconnection problem with adequate resolution.